Registered Respiratory Therapist (RRT-TMC) Practice Exam

Elevation of the right hemidiaphragm on a chest radiograph is a sign of reduced volume on that side or upward displacement from below. When the right lower lung loses volume due to atelectasis, the diaphragm is pulled upward. An enlarged liver (hepatomegaly) beneath the diaphragm pushes it upward from below. A lower-lobe consolidation with air bronchograms also reduces aeration and volume in the right lower zone, leading to diaphragmatic elevation. The finding described as right-sided hyperlucency with absent vascular markings points to a pneumothorax—air in the pleural space. This pattern reflects a different mechanism (pleural air with loss of vascular markings beyond the pleural line) and does not classically produce the same diaphragmatic elevation from lower-lung volume loss. Hence, it is the exception.